I. Field of the Invention
This invention relates generally to dollies for supporting the tongue-weight of utility trailers and, more particularly, to a dolly having the ability to shift the tongue-weight of a towed trailer to increase traction of either the wheels of the dolly or the wheels of a towing vehicle, such as an all-terrain vehicle (ATV) or a utility task vehicle (UTV).
II. Discussion of the Prior Art
Trailers of various designs, such as box trailers, lawn and garden utility trailers and the like, are designed to be towed by an ATV or garden tractor. A heavily loaded, two-wheel trailer often results in an excessive tongue-weight being applied to a ball hitch mounted on the rear of the garden tractor or ATV and which, over time, can result in damage to the tractor's transmission. Trailer dollies have been devised to join a trailer to a towing vehicle. See, for example, U.S. Pat. No. 2,534,575 to Conley et al, U.S. Pat. No. 2,844,389 to Burnett, U.S. Pat. No. 3,865,405 to Mitchell et al and U.S. Pat. No. 4,491,338 to Sheldracke. See also applicants' earlier U.S. Pat. No. 7,845,670.
Prior art trailer dollies typically may comprise a frame supported by a wheel and axle assembly and carrying a hitch ball whose height above the frame is adjustable. A draw bar is joined to the front end of the frame and includes a coupler at its proximal end for coupling the dolly to a ball hitch on a towing vehicle. The height adjustment hitch ball on the dolly frame provides an attachment point for a trailer to be towed. By incorporating the dolly between the towing vehicle and the trailer, the tongue-weight of the trailer is supported primarily by the dolly and not by the hitch receiver on the back of the towing vehicle. While this is an advantage during on-road trailering as far as better control of the towing vehicle is concerned, it may have a drawback in off-road trailering applications. Where a garden tractor, an ATV or a UTV is being used to pull a heavily loaded trailer or to move a fish house on or from a frozen lake, more weight is often required on the rear wheels of the towing vehicle to provide sufficient traction, especially on sand, in mud, on loose soil or in snow and ice.
It is accordingly a principle object of the present invention to provide an improved trailer dolly that allows the tongue-weight of a trailer being towed to be shifted from a location directly over the wheel and axle assembly of the dolly to a location where more of the tongue-weight is applied to the rear wheels of the towing vehicle.